Powertrain, generic (extended)

P24DE Reductant Purge Control Valve B Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

With P24DE the control line of purge valve B stays at high voltage while the controller is actually pulling it to ground to switch the valve. That points to a short to the battery feed on the wire between valve and controller, or a valve coil with too little resistance, so that the driver protects itself and the valve never shifts. No manufacturer documents P24DE publicly. For valve A, GM runs the equivalent P20A3 check while the driver is switched on (6.6 L Duramax). CARB requires heavy-duty SCR actuators to be checked for this kind of circuit fault. The consequence is the reverse of P24DD: the valve stays in dosing position, so the line is not emptied at shut-down and can freeze. Interruptions are P24DB, the functional test P24DC.

Likely causes

Control wire touching a supply line
Valve coil with shorted turns and too low resistance
Damaged driver stage in the control module

Symptoms

  • Malfunction indicator lamp on
  • DEF line not purged, frozen line after frost

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,500
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant purge valve b

Related codes

P24DBP24DDP20A3

References: gsi.ext.gm.com, law.cornell.edu.